Patient, kidney, and pancreas survival in pancreas after kidney transplantation versus simultaneous pancreas and kidney transplantation: meta-analysis

Both pancreas after kidney transplant (PAK) and simultaneous pancreas and kidney transplant (SPK) are treatment options for patients with type 1 diabetes (T1DM) and end-stage kidney disease (ESKD), but they have different risks and benefits. . PAK is for patients while waiting for transplantation and to increase the survival of allograft

Presently, SPK is more widespread than PAK because SPK requires only one operation 1 . PAK is a recommended option for patients with living kidney donors to avoid long-term uraemia while waiting for cadaveric pancreas transplantation and to increase the survival of allograft kidney transplantation 2 . The aim of this study was to compare PAK and SPK in terms of patient, kidney, and pancreas survival.
Online databases were used to locate studies of patient with T1DM and ESKD undergoing PAK and SPK up to 20 January 2022 (Supplementary material and Fig. S1). A total of 47 986 patients were identified from 24 studies, including 9093 patients undergoing PAK and 38 893 patients undergoing SPK (Table S1). Patient, kidney, pancreas survival rate as well as human leucocyte antigens (HLA) mismatch rate in patients undergoing PAK versus SPK at 1, 3, 5, and 10 years in the included studies are shown in Table 1. Quality ranged on the Newcastle-Ottawa Scale from six to nine (Table S2). The definitions of pancreas and kidney rejection, the rejection ratios of PAK and SPK, and the details of the rejection treatment used in all the included articles are given in Table S3.
Patients with PAK had a significantly higher 1-year patient survival than patients with SPK (OR 1.11, 95 per cent c.i. 1.00 to 1.24), whereas patients with PAK had a lower 10-year patient survival than patients with SPK (OR 0.73, 95 per cent c.i. 0.67 to 0.79) (Fig. S2) Patients with SPK have better long-term survival than patients with PAK, which may indicate that rejection is difficult to detect without simultaneous kidney transplantation 3 . Kidney graft survival in PAK is significantly better, in part due to selection bias, as only recipients with good renal function after kidney transplantation will proceed to pancreas transplantation. Another main reason for higher kidney graft survival in the PAK group was that the proportion of living donors was significantly higher. The pancreas graft long-term survival rate in PAK is still slightly lower than that of SPK, and an adverse pancreas outcome after PAK may be due to technical complications and immunological issues 4 . Higher graft survival yields lower mortality and preventing both immune and non-immune causes of graft failure is critical in reducing post-transplant mortality 5 .
This study has some limitations, the studies included a large range of years, and earlier transplantation technology had a certain impact on the patient survival and graft survival of the two groups (SPK versus PAK recipients had a higher incidence of kidney graft loss due to technical reasons in 2000: 2.1 per cent versus 0 per cent . At present, the technical failure rate of SPK as a cause of allograft failure is similar to that of PAK). Furthermore, limited to the results in the included literature, the effects of other post-transplant complications, such as thrombosis, infection, obesity, smoking, and coronary heart disease, were not taken into account.

Funding
The authors have no funding to declare.

Disclosure
The authors declare no conflict of interest.

Supplementary material
Supplementary material is available at BJS Open online.

Data availability
The data underlying this article are available from the corresponding authors upon request.